A new study in France found that chronic consumption of refined carbohydrates between meals was associated with poorer cognitive performance in both men and women. This effect persisted even when energy intake and a number of other factors were controlled. The study was published in Personality and individual differences.
Each animal species is adapted to a specific diet. Their digestive processes tend to be specialized for efficiently digesting a certain type of food. Therefore, when their diet suddenly changes, it usually leads to health problems because the digestive system is not adapted to the new types of food.
For most Westerners, a major change in diet occurred in the second half of the 20sth century when industrialized foods began to become commonplace. These foods often contain high concentrations of refined carbohydrates—primary sucrose, low-fiber gelatin starches, high-sugar corn syrup, and others.
This change in diet has been associated with an increase in the incidence of obesity, type II diabetes, cardiovascular disease, tooth decay, hypertension and many other diseases. It is now believed that the physiological mechanisms involved in the development of these diseases include repeated excessive concentrations of glucose (hyperglycemia) and insulin (hyperinsulinemia) in the bloodstream, accompanied by a lower sensitivity of cells to the effects of insulin (insulin resistance). . Glucose is a simple sugar that is the main source of energy in our body, while insulin is a hormone that facilitates the uptake of glucose into the cells.
Study author Leonard Guilloue and his colleagues wanted to investigate whether consumption of refined carbohydrates affects cognitive performance in healthy young adults. They noted that studies of the long-term effects of carbohydrate consumption have so far been conducted mostly in older people and in the context of certain diseases. Data on the effects of chronic consumption of refined carbohydrates on young, healthy adults are lacking. They set up an experiment.
Participants were 95 healthy young people between the ages of 20 and 30 recruited at the University of Montpellier in France. They came in groups of 3-4 people early in the morning to the laboratory. The researchers first measured their blood sugar level. Participants then completed a cognitive assessment test (Wechsler Digit Symbol Substitution Cognitive Test). They were then served one of two types of snacks.
Each type of breakfast contained 500 kilocalories, but one was composed of unrefined carbohydrates (whole wheat bread, butter, cheese, raw fruit and an unsweetened drink) and the other of refined carbohydrates (a French baguette made from industrially ground flour, jam, fruit juice and an unsweetened drink with sugar).
The breakfast to be served was randomly selected each day. After breakfast, participants completed questionnaires about their demographic characteristics, physical activity levels, and dietary habits. One and a half hours after breakfast, the participants’ blood sugar level was measured again and they completed another cognitive assessment (Wechsler cognitive test). Between these steps, the researchers measured the height and weight of the participants.
The results show that 40% of men and 54% of women eat afternoon snacks (corresponding to Afternoon tea, traditional afternoon snack or tea time). 25% of men and women ate snacks between meals. Higher consumption of refined carbohydrates between meals and higher energy intake in the afternoon snack were associated with poorer cognitive outcomes.
A similar but weaker relationship was observed for energy intake at breakfast. Breakfast consumed on the same day was not associated with cognitive performance. Men, but not women, with higher BMI values tended to perform worse on cognitive assessments.
“The recent Western dietary change, characterized mainly by a huge increase in the consumption of refined carbohydrates, has well-known adverse health effects. “Given the growing number of people affected by these pathologies and the repeated failure of many medical treatments, our study reinforces the belief that the most promising research should focus on prevention in healthy people,” the study authors conclude.
The study makes a valuable contribution to scientific knowledge about the links between dietary choices and cognitive outcomes. However, it should be noted that the study design does not allow for any causal inferences. It is possible that higher consumption of refined carbohydrates between meals leads to reduced cognitive performance, but it may also be that people whose cognitive performance is worse tend to eat a lot of refined carbohydrates between meals. These are not the only possibilities.
Learning, “Chronic consumption of refined carbohydrates as measured by glycemic load and variation in cognitive performance in healthy humans,” is authored by Leonard Guilhoud, Valerie Durand, Michelle Raymond, and Claire Berticat.
Leave a Reply